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The Absolute Intensities of the γ-Rays of Radium B and Radium C

Published online by Cambridge University Press:  24 October 2008

C. D. Ellis
Affiliation:
Trinity College
W. A. Wooster
Affiliation:
Peterhouse

Extract

Considerable advances have been made in recent years in our knowledge of the γ-ray emission of radioactive bodies. It has been established quite definitely that series of definite frequencies are emitted, forming a characteristic line spectrum of the nucleus, and methods of measuring the frequencies have been devised so that at present the γ-ray spectra of most of the radioactive bodies are well known.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1927

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References

* Ahmad, , Proc. Roy. Soc. 109, p. 207. 1925.CrossRefGoogle Scholar

Kohlraugoh, , Phys. Zeit. 28, p. 1. 1927.Google Scholar

* Loc.cit.

Loc. cit.

Thibaud, , Journ. de Phys. 34, p. 807. 1925.Google Scholar

* It will be seen later that, while advantageous, it is not necessary to depend on the counting measurements, but the method is most easily explained by referring to them.

* Ellis, and Wooster, , Proc. Roy. Soc., March 1927.Google Scholar

* Ellis and Wooster, loc. cit.

* Kovarik, , Phys. Rev. [5], p. 559. 1924. See also footnote to equations (10) and (11) later.CrossRefGoogle Scholar

Assuming 3·4 × 107 atoms disintegrate per sec. from 1 mg. This figure is used throughout this paper; any variation in this figure will only affect the value of “g” and not f(V).

Ellis, and Wooster, , Phil. Mag. [6] L, p. 521 (1925).CrossRefGoogle Scholar

* Phil. Mag. [6] xxviii, p. 527 (1914).Google Scholar

Ib. [6] xxv, p. 312 (1913).Google Scholar

Ib. [6] xxiii, p. 302 (1912).Google Scholar

§ Ib. [6] L, p. 521 (1925).Google Scholar

* The frequent appearance of the factor 1·03 in these equations is due to the slightly larger values of the internal conversion coefficients for radium C. It will be noted that the above equations give simply the energies and numbers of the γ-rays emitted from the nucleus before conversion takes place.

It is generally recognised that the counting of γ-rays is an extremely difficult experiment, and so our results based on these measurements might appear to be open to doubt. It has been suggested that Kovarik's figure might be too large, owing to a high speed photo-electron giving rise, by collision, to another fast electron. We do not share this view, and consider Kovarik's experiments may be used with safety, but it is most important to note that, in point of fact, we could dispense with these measurements altogether. Using equations (12) and (13) we could deduce values of “g” and f(V), which we should then have to justify on general grounds. Then with these values we could use equations (10) and (11) to calculate the number of γ-rays emitted.

* Were we to leave out the counting measurements we should decide on a variation with the 2·7 power and a value for g of 0·17. This would put still more energy in the high frequencies.

* Ahmad, loc. cit.

* Loc. cit.